Abstract

We describe antibody isotype patterns resulting from Schistosoma japonicum infection among 155 individuals 5–76 years old from a community in Leyte, The Philippines. Their exposure, infection, and reinfection status had been observed in a previously described water contact study used to categorically classify them as putative resistant or susceptible individuals. Antigens tested for specific antibody isotype responses were soluble worm antigen preparation (SWAP) and soluble egg antigen (SEA) and a panel of recombinant molecules. The study was aimed primarily at evaluating antigen-specific antibody responses and their potential in inducing protection among putative resistant individuals. Specific antibody responses suggestive of an involvement in protection were an IgE response to SWAP among females less than 20 years of age (5–19) and IgA responses to SWAP in the younger (5–19 years) age groups. Compatible with other studies on human schistosomes, IgM reactivities to SWAP and SEA in the 5–19-year-old age group predicted susceptibility as did IgG4 responses to recombinant paramyosin.